Bare with me, I know I'm asking a lot of really basic questions lately, but I'm getting some really good basic answers and I like those.
I just stuck a 7 speed freewheel on my old Raleigh. Don't really need 7 speeds but it's got the right ratios and it's a Hyperglide and that makes me happy. Anyway, I ended up adding a 2mm spacer to get that last gear in and there's only a teeny bit of axle left for the dropout. To make things really silly, I was thinking, rather than go to all the trouble of redishing this wheel (again) why don't I just stick another 2mm spacer on the left side (for a total of 132mm)?
Now I need an axle, I should probably get an axle either way (redish or just respace). I've got one that's long enough from a cheap chinese MTB but it's nutted. Maybe I should just stick it in there and ride it till something goes wrong or maybe I should bring it up here and get some good learning in.
I've heard that hollow axles for quick release skewers are stronger but I heard it from a less than reliable source and with no real explanation. Are QR axles made from better steel?
How much difference is there between this Campy axle I have (too short, of course) and this dumb chinese axle is there really?
Thanks for being patient with me.

Take te axle out and redo the spacing to the drive side with thinner lock nut to the non drive side and you should have enough space for the 7 speed freewheel. 2mm on the drive is nothing to worry about for a well maintained wheel. QR axle if not properly adjusted will break. most QR axles are cromoly or heat treated and solid axles aren't, although wheels manufacturing does make a solid cromoly axle if needed.